Comment 7 for bug 1455223

(not directly related to bug, but a workaround since the indicator is a bit buggy in vivid, and this bug seems to represent the problem well)

Thought others may be interested in this script:

#!/usr/bin/python3
import subprocess
import json

tz = [
    "America/Los_Angeles Los Angeles",
    "America/Denver Denver",
    "America/Sao_Paulo São_Paulo",
    "UTC UTC",
    "Europe/London London",
    "Asia/Kolkata India"
]

subprocess.check_call(
    ["gsettings", "set",
     "com.canonical.indicator.datetime",
     "locations", json.dumps(tz)])

Simply customize, run and it should fix up timezones for you.